The "Mexican Revolution" is not an easy thing to define, even in a strictly political sense: it can easily be defined as spanning the years from 1910 through World War II, and arguably it has simply never ended, the current Zapatista movement in Chiapas and elsewhere being an extension of the same fundamental conflict.
I have noticed, in speaking with Mexicans, that they refer to the conflict not as "the Mexican Revolution" so much as they do "the Civil War," indicating a perspective that better describes the conflict - there were many sides, fading into and out of each other, with as many as six distinct armed political entities fighting among themselves at a single time.
The conflict is one concerning land and the basic livelihood of the peasants, with a layer of more typically European "Marxist" struggle existing in the cities. Mexico under Porfirio Diaz became a dictatorship that increasingly denied the rights of the poor in favor of the existing landed gentry and urban elites. This situation became unbearable and errupted into armed violence in 1910-1911, triggered by Diaz' heavy-handed behavior in the presidential elections. In 1920, the period of intensive violence ends with the ascension of Obregon to the presidential seat, after a concerted effort to negotiate a peace with the various factions. This period is the one described here, although neither the Revolution nor armed conflict for revolutionary causes had by any means ended.
Wargamers seem to have largely ignored this period, with the possible exception of Pershing's futile expedition across the Rio Grande in pursuit of Pancho Villa. Despite this, the period offers us an excellent situation for miniatures wargaming. It combines WWI-era machineguns and artillery with a "Wild West" flavor, featuring lots of cavalry, railroads, etc. There were even a few armored cars. The forces ranged from the typical skirmishes to huge battles between divisional- and corps-sized units. It is easy to find figures for the different combatants from Wild West, America Civil War, WWI, and Colonial lines - there are even a few figures made specifically for this conflict.
This article attempts to outline the political conflict in a high-level overview, so that gamers can understand the basic conflict. A simple set of rules are offered elsewhere on this website.
Madero enters race against Diaz, who has Madero jailed to keep him out of the running. Diaz wins the rigged election, but the populace is unconvinced and he is unpopular. Madero issues a call to arms against Diaz, in the "Plan of San Luis Potosi."
In Chihuahua, General Orozco seizes a military convoy. Madero - an incompetent military leader - leads an attack at Casas Grandes in Chihuahua, but is crushed. (He decides to stick to politics.) He is wounded in the fighting in the area subsequently. Battles occur at Agua Prieta, Son., and at Tiajuana. Generals Orozco and Villa capture Cuiadad Juarez. This triggers Diaz' resignation, leaving an interim president, according to the terms of the "Treaty of Cuidad Juarez." Madero wins the subsequent elections.
Orozco and Villa break with Madero over his clemency to General Navarro, captured by them at Cuidad Juarez. (The two of them subsequently have a falling out, when Villa refuses to join Orozco in a rebellion against Madero.)
In Morelos, Zapata leads a revolt against Madero on a platform of land reform. He accuses Madero of betraying the Revolution, and lays out his program in the "Plan of Ayala." He sets himself up as the de facto ruler in Morelos, and starts to collectivize the haciendas, etc.
General Orozco releases the "Plan Orozquista," calling for social reforms and distribution of publically-held lands. He is supported by one of the major land-owning families. His plan also calls for Madero's removal, and the nationalization of Mexican railroads. He has an army of some 6,000 men behind him. Porfirio's nephew, Felix Diaz, raises another army from the conservative elements wishing a return to the stability of his uncle's regime, near Vera Cruz. Felix Diaz is captured by government troops and imprisoned in Mexico City. In prison he meets and conspires with Bernardo Reyes against Madero.
Villa fights with Orozco's rebels in the north, first capturing and then losing Parral. Villa joins forces with Huerta, Madero's field commander in the north. Villa is subsequently sentenced to be shot for insubordination, but Madero has him imprisoned instead.
Felix Diaz escapes from prison, and plans a coup (with Bernardo Reyes and others), leading to ten days of intense fighting in the capitol, the "Decena Tragica." (Villa, invited to join Reyes while in prison, refuses, before escaping and fleeing to the U.S.) Following this, Huerta, conspiring with Lane, the American ambassador under president Wilson, betrays Madero under the "Pact of the Embassy." Sent to quell a minor rebellion, he has General Aureliano Blanquet march into the National Palace and arrest Madero, his brother, and most of his cabinet. Huerta assumed power in Mexico, as president, and has Madero, his brother, and his vice-president killed "while trying to escape."
In response to this, Carranza declares his opposition to Huerta's government from Coahuila, calling on all of the generals and governors of the different states, in his "Plan of Guadalupe." Pancho Villa comes back into Mexico, declaring his support for the pro-Madero Carranza, and begins his campaigning in the north. He captures Torreon, and becomes governor. He wins subsequent battles at Cuidad juarez and Tierra Blanca. General Alvaro Obregon also joins Carranza.
The "Ley Juarez" is invoked against Huerta and his supporters, declaring them traitors and subject to death. Ugly rumors become substantiated about the circumstances of Madero's death and the complicity of Lane, the American ambassador. Huerta dissolves both houses of the Mexican Legislature when they begin to investigate these rumors.
Huerta has lost control of three-quarters of Mexico, now effectively rules by various revolutionary factions. He maintains power only around Mexico City. Woodrow Wilson, suspicious of Huerta, uses the affair of the U.S.S. Dolphin to escalate a misunderstanding into the seizure and six-month occupation of Vera Cruz by U.S. Marines and Naval contingents. Some fighting with Mexican government troops occurs. The U.S. becomes incredibly unpopular in Mexico, and Huerta, whose position has been made untenable by Carranza, Villa, and others, resigns as president, blaming U.S. interference for Mexico's internal problems. He is shortly followed into exile by Carbajal, his successor.
Villa continues to campaign in the north, taking Ojinaga and Saltillo. He has a falling out with Carranza over plans to capture Zacatecas (which Villa does, but against Carranza's wishes). Obregon captures Guadalajara, and then moves on to occupy Mexico city for Carranza. Villa declares war on Carranza.
Carranza holds the Convention of Auguascalientes in Mexico City, to determine who should be interim president. He is, of course, chosen, but threats by Villa to invade Mexico City cause him to postpone the event, and move it to Auguascalientes, a "neutral" town. Eventually, after heavy politicking, Guterriez is chosen as president, and he declares Carranza to be a rebel, appointing Villa to be overall commander of both the "Convention" armies. Obregon assumes actual control of Carranza's army, and pulls it back to Vera Cruz. Villa and Zapata "race" to Mexico City, with Zapata arriving a week before his rival. They meet at Xochimilco, where they form the "Xochimilco Pact," avoiding further violence, but going their separate ways.
The "Year of Hunger" begins, with chaos everywhere and starvation commonplace in Mexico City - the national infrastructure has broken down to the point where food shipments do not reach the city. The first part of the "War of the Generals" starts with Obregon driving Zapatista forces from Puebla, and marching on Mexico City with his "Operational Army." He ends up taking the capitol and forcing Guterriez to flee. Mexico now has a bewildering array of self-proclaimed governments:
Further, Felix Diaz continued his politicking from the Vera Cruz area, particularly with some of the Zapatista generals. Ostensibly, Obregon was a supporter of Carranza, but things were not so simple in reality, naturally.
Obregon raises the armed support of the trades unions in Mexico City (the "Red Battalions"), and marches north against Pancho Villa. The Unites States recognizes Carranza as the real president of Mexico, and the governor of Oaxaca, Davila, declares that the state has reassumed individual sovereignty. Villa and Obregon fight a series of long and bloody battles at Celaya, Trinidad, and Auguascalientes, with Obregon emerging triumphant, and eventually clearing Villa's forces from the north. (Villa is chased back into his mountain strongholds with a few hundred supporters.) Obregon has a good deal of trouble with the U.S., entering the U.S. (with permission) to fight against Villa, but also causing a good deal of trouble on the border in the form of raids and general unrest in border towns. Blamed on Villa, agreements are ultimately reached with the U.S. around support for Carranza, and the Obregon-inspired "troubles" cease.
The fighting shifts to a conflict between the followers of Zapata and Carranza. In Morelos, the Zapatistas are beaten at Tlatizapan and are forced to retreat into the mountains by the Carrancistas. Pershing, who has been busy chasing Pancho Villa around the north, begins to annoy Carranza - he requires that all U.S. troop movements in Mexico be north, toward the border. Meanwhile, President Wilson has mobilized the national guard and has units ready on the border.
The Zapatistas have reorganized, and manage to capture the main water-pumping station feeding Mexico City. They also regain ground lost in Morelos, after a series of Carrancista atrocities there. Meanwhile, Pancho Villa has amassed 5,000 men, and seizes Torreon again.
There is a good deal of labour unrest in Mexico City at this time, and the "Red Battalions" are disbanded. The population as a whole is not supportive of Carranza's regime, in the country or in the city. Obregon uses the rift between workers - who are being strong-armed by the Carrancista regime - and the government. Velasco, a labour leader, is jailed, but Obregon arranges to have him freed, and for the labour unions to keep a low profile.
In January, Pershing finally withdraws over the border. In February, a six-week effort at Queretaro produces the Constitution of 1917. When Carranza is elected president (although not recognized as legitimate by the Zapatistas), it becomes evident that he has no intention of enforcing the new constitution. Carranza and Obregon break openly. The trades unions back Obregon.
The Spanish influenza epidemic sweeps Mexico, killing thousands. General Gonzales takes his Carrancista forces into Morelos, and again occupies the cities, fighting with Zapatista forces, much reduced by the flu epidemic, who take to hiding in the mountains.
Carranza has Zapata assassinated at Chinameca. Obregon declares himself as a candidate for the presidential elections the following year, against Carranza's chosen candidate, Bonillas.
Obregon is summoned to Mexico City by Carranza, to be killed, but friends help him to escape. Obregon declares a rebellion against Carranza, who flees the city, only to be assassinated at Tlaxcalantongo, Puebla. Adolfo de la Huerta becomes provisional president, following which Obregon is elected.
Villa was assassinated in 1923, after accepting terms from Obregon to preserve the peace. His assassins were never punished.